The invention relates to a blading for a turbomachine, in particular an internal combustion engine having at least one compressor stage, combustion chamber and turbine stage, preferably a gas turbine in which thickened areas and depressions are formed on a lateral wall having a plurality of blades, and a manufacturing method for such a blading.
A blade passage of a turbomachine is generally defined by a hub-side and a housing-side lateral wall as well as guide vanes or rotating blades disposed therebetween, each of the lateral walls being able to be fixed relative to the hub or housing. Increased deflections of the flow may occur in blade passages due to the effect of wall friction in the region of the lateral walls, whereby in part strongly pronounced secondary flows result. These secondary flows cause increased losses.
A blading for a turbine is known from EP 1 995 410 A1, in which thickened areas and depressions are formed on a lateral wall having a plurality of blades. Bladings for turbines or turbomachines are known from EP 2 248 966 A1 and DE 32 02 855 C1, in which elevations are formed on a lateral wall having a plurality of blades.
The object of the present invention is to provide an improved blading and a method for the manufacture thereof.
This object is achieved by a blading with at least one depression disposed on a blade pressure side and at least one thickened area disposed on a blade suction side for each blade of the plurality of blades, as well as by a manufacturing method for a blading wherein the blade has a bent, particularly orthogonal transition in the region of the transition from blade to lateral wall. Advantageous enhancements are the subject of the dependent claims.
According to one aspect of the present invention, in the case of a blading for a turbomachine, in particular a compressor stage or turbine stage of an internal combustion engine, preferably a gas turbine, in which thickened areas and depressions are formed on a lateral wall having a plurality of blades, for each blade of the plurality of blades, at least one depression is disposed on the pressure side of the blade and at least one thickened area is disposed on the suction side of the blade.
By this targeted combined introduction of thickened areas and depressions on the pressure or suction sides, respectively, an advantageous local adaptation of the static pressure and the flow velocity can be achieved, whereby secondary flows can be influenced advantageously and flow losses can be reduced. In addition to the reduction in losses in the blade channels over a large operating range of turbomachines, another advantage of this configuration also may lie in an enlarging of the operating range of turbomachines. An advantage may also lie in a simple structural conversion and/or applicability for already existing designs of turbomachines.
As blading in the sense of the present invention, an arrangement of rotating blades and/or an arrangement of guide vanes, in particular of one or more stages, is particularly intended. A blading according to the invention is particularly suitable for high-pressure compressors. In a preferred embodiment, an aircraft engine has a blading according to the invention.
A lateral wall in the sense of the present invention can be on the hub or rotor side, and/or the housing side and can be fixed on the hub or rotor, and/or the housing. Thus, a lateral wall may comprise the hub-side, i.e., radially inner and hub-fixed peripheral face of a rotating-blade grid, and/or the housing-side, i.e., radially outer peripheral face of a rotating-blade grid, which can be formed, in particular, by a shroud fixed to the hub or by an inner face fixed to the housing. Likewise, a lateral wall may comprise the housing-side, radially outer peripheral face and/or the hub-side peripheral face of a guide-vane grid, which can be formed, in particular, by a shroud fixed on the housing or an outer face fixed on the hub.
In the sense of the present invention, a depression is to be understood particularly to be a region of the lateral wall that is offset radially inwardly relative to other regions of the lateral wall, while a thickened area or elevation in the sense of the present invention is to be understood particularly to be a region of the lateral wall that is offset radially outwardly relative to other regions of the lateral wall. A depression or thickened area in the sense of the present invention may be recessed or extended radially inwardly or outwardly, respectively, in particular, in relation to a particularly straight or curved reference conical surface that lies concentrically to an axis of rotation. The reference conical surface, in particular, can run through the radially innermost or radially outermost points of the lateral wall or therebetween. In particular, the radius of the reference conical surface may correspond to the average of the maximum and minimum or all radial extensions of the lateral wall. In addition, the depression or thickened area may also relate to a reference conical surface that runs through a non-contoured region of the lateral wall or a root or a tip of the blades.
In the sense of the present invention, a thickened area can be understood, in particular, as a radial dimension that is larger in comparison to the depression, while a depression is understood correspondingly as a radial dimension that is smaller in comparison to the thickened area.
For example, if one considers a sinusoidally channeled lateral wall in the peripheral direction, then the mountains or valleys represent thickened areas or depressions, respectively, relative to the central line, in the sense of the present invention. Likewise, one can proceed from a reference conical surface through the radially maximum or minimum amplitudes of the sinusoidally channeled lateral wall. Here also, the valleys represent depressions and the mountains represent thickened areas relative to this reference conical surface, since they lie in contrast radially further in (or further out).
The lateral wall is preferably not contoured in the axial direction in front of and/or behind the pressure-side depressions and/or suction-side thickened areas, i.e., it has the same radius over the entire circumference of a radial section.
In a preferred embodiment, a depression disposed in the region of the pressure side of the blade and/or a thickened area disposed in the region of the suction side of the blade, viewed in the direction of flow, begins in front of or in back of the leading edge of the blade.
A depression disposed in the region of the blade's pressure side and/or a thickened area disposed in the region of the blade's suction side in the axial direction preferably extends over at least 10%, preferably at least 30%, of the axial grid length, measured between the leading and trailing edges of the blade.
In a preferred embodiment for the blading, the thickened area disposed in the blade's suction side and/or the depression disposed in the blade's pressure side is (are) disposed in the axial half of the blade grid adjacent to or facing the inlet side.
A second thickened area in the half adjacent to the outlet side is preferably disposed extending in each case from the blade's suction side to the blade's pressure side, for the blading. In this configuration, the second thickened area can be disposed and configured peripherally symmetrical. Alternatively, the second thickened area can be disposed and configured peripherally asymmetrical. The second thickened area can extend preferably in the peripheral direction from one blade to the adjacent blade. In the axial direction, the second thickened area can extend over at least 10% of the axial grid length in a preferred embodiment. The second thickened area can be radially higher or lower than the thickened area disposed on the suction side of the blade.
The present invention can preferably be applied in blade grids that have a bent, particularly at least substantially orthogonal, transition from the blade's pressure side and/or suction side to the lateral wall; likewise also in the case of blade grids that have a rounded root area in the transition region from the blade's pressure side and/or suction side to the lateral wall.
According to another aspect of the present invention relating to the manufacturing method, in the case of a manufacturing method for a blading for a turbomachine, at least one original shaping, reshaping and/or cutting treatment is executed in such a way that in the case of a lateral wall having a plurality of blades, thickened areas and depressions are formed, at least one depression being formed on a blade's pressure side and at least one thickened area being formed on a blade's suction side for each blade of the plurality of blades.
Advantageously, a blading having a high efficiency, particularly in a rapidly rotating high-pressure compressor (stage) can be provided by the configuration according to the invention.